392 A. T. RASMUSSEN AND J. A. MYERS 



found tliiit the \issl bodies had greatly diminished in size and 

 the acido])lul p-aiiules had become basophiUc during winter- 

 sleep; but in liibernating mammals no changes were observed. 

 A more detailed study by Legge ('99), however, led this author 

 to conclude that the cells of the cerebro-spinal axis of hibernating 

 bats do undergo visible changes. In the cells of the cerebral 

 cortex he found the Nissl granules to have elongated, being more 

 fusiform in shape, and to be displaced towards the periphery, 

 forming a sort of envelope to the cytoplasm. Baroncini and 

 Beretta ('00) also reported morphological changes in the spinal 

 cord and especially in the cerebral cortex of mammals (mus- 

 cardin and bat) during winter-sleep. They found that the 

 Nissl granules had greatly decreased and stained more diffusely. 

 The chromatic substance of the nucleus was also more diffuse 

 than in active specimens and the nucleolus seemed to have 

 disappeared in many cases. Essentially the same changes in 

 the Nissl granules in the cells of the cerebro-spinal axis and in 

 the Purkinje cells of the cerebellum of hibernating hedgehogs, 

 were reported by Marinesco ('05) w^ho found a distinct decrease 

 in these granules during the torpid state. Those that remained 

 were reduced to fine granules or were diffused in the cytoplasm. 

 A more recent study by Zalla ('10) agrees with the older results 

 obtained by Levi in regard to mammals. Zalla found no ap- 

 preciable morphological difference in the Nissl substance in the 

 dormouse (Myoxus glis) during hibernation as compared with 

 the active state. His results in amphibia were not constant, 

 but in reptiles he found a distinct decrease in this substance in 

 the motor cells of the cord and pons during winter-sleep. 



The question of changes in the chromophilous substance of 

 the nerve cells during hibernation in mammals thus seems to 

 be unsettled. Legge, Baroncini and Beretta, and Marinesco 

 apparently have observed marked changes, while Levi and Zalla 

 could not establish any such chromatolysis. However, these 

 authors did not all work on the same species of mammal. In 

 amphibia there is also some disagreement. Levi found a dis- 

 tinct decrease in the Nissl granules during hibernation, while 

 Zalla, whose results were not very constant, believes that there 



